Investigating the molecular mechanisms regulating protein ubiquitylation in skeletal muscle following physical activity

Physical activity is a well-established physiological stimulus for improving whole-body health. When performing physical activity, the body is highly dependent on skeletal muscle tissue due to its role in both locomotion and metabolism. As a result, physical inactivity impairs skeletal muscle mass and function, resulting in metabolic diseases and ageing. The role of protein ubiquitylation for controlling skeletal muscle mass and function has become widely accepted. However, the response of protein ubiquitylation following exercise is poorly researched, especially in relation to the molecular mechanisms involved. To address this knowledge gap, my PhD project aims to investigate how protein ubiquitylation is regulated in skeletal muscle following physical activity. To do this, this project will be focusing on the response of both E3 ligases and de-ubiquitylating enzymes following acute exercise. E3 ligases enable the transfer of ubiquitin onto a protein substrate, whereas de-ubiquitylases (DUBs) reverse this reaction and remove the ubiquitin from the substrate. Therefore, these enzymes are the key molecular mechanisms regulating protein ubiquitylation. Firstly, we aim to determine which E3 ligases and DUBs are altered in response to exercise, providing us with a list of candidate enzymes to focus on. Next, we will examine their substrates through mass-spectrometry to better understand the signalling pathways involved. Finally, we will employ a sensitive proteomic approach to investigate the exercise-regulated ubiquitylome in human skeletal muscle. Together, this project will improve our understanding of exercise-regulated protein ubiquitylation, exposing a new layer to skeletal muscle biology.